Problem: Simplify to lowest terms. $\dfrac{40}{15}$
Solution: What is the greatest common factor (GCD) of 40 and 15? $40 = 2\cdot2\cdot2\cdot5$ $15 = 3\cdot5$ $\mbox{GCD}(40, 15) = 5$ $\dfrac{40}{15} = \dfrac{8 \cdot 5}{ 3\cdot 5}$ $\hphantom{\dfrac{40}{15}} = \dfrac{8}{3} \cdot \dfrac{5}{5}$ $\hphantom{\dfrac{40}{15}} = \dfrac{8}{3} \cdot 1$ $\hphantom{\dfrac{40}{15}} = \dfrac{8}{3}$